US forces in Saudi Arabia and Kuwait were put on the highest security alert Monday because of a "credible threat" of terrorist attacks against unspecified targets, the Pentagon said Tuesday.

"In both Saudi Arabia and Kuwait, US forces are now on the highest alert level," Pentagon spokesman Kenneth Bacon said.

"It is due to credible threat information involving unspecified targets," he said.

The latest actions raised to five the number of countries in the region where US forces have gone to the highest alert level in response to threats since the October 12 bombing that killed 17 US sailors and crippled a billion dollar destroyer in the Yemeni port of Aden.

Threat condition delta normally is invoked either after a terrorist attack has occurred or intelligence indicates a terrorist action against a specific location is likely.

US forces in Bahrain and Qatar were put on the highest alert level on October 21 in response to multiple threats of attacks against specific locations, and US forces in Yemen went to threat condition delta immediately after a small boat blew a 12 by 12 meter (40 by 40 foot) hole in the USS Cole.

The last time US forces in the region were put on threat condition delta was after the 1998 bombings of the US embassies in Kenya and Tanzania that killed 224 people.

In a related development, the navy said no US warships have gone through the Suez Canal since the suicide attack on the USS Cole.

"The Cole was the last ship to transit the Suez," said Lieutenant Meghan Mariman, the navy spokeswoman. "We have not sent any other ships through there since the US attack on the Cole."

US officials, meanwhile, have been holding talks with Egyptian authorities about security at the canal and whether it is "appropriate for the perceived threat," another Pentagon official said.

"Everything is pretty much on hold right now," said a Navy official, speaking on condition of anonymity. "We have not diverted any ships to go around Africa, but also have not sent any ships through the Suez."

Bacon, however, denied that a decision has been taken to keep US warships out of the canal, and said that only one ship had been scheduled to go through it after the Cole.

That ship -- the USS Donald Cook -- has now been assigned to escort the Norwegian ship that will haul the Cole back to the United States.

The Pentagon is considering routing the Blue Marlin around Africa, a five to six week voyage, rather than make the two to three week voyage home through the canal, said Navy Lieutenant David Gai, a Pentagon spokesman. He said no decision has been made.

The Cole was still being loaded onto the Norwegian ship Tuesday and would not be ready to begin the voyage home for several days, officials said – WASHINGTON (AFP)